Dave, that is what I found out when I was in Australia,
The OP AFAIK lives there.

When I was in the land of Oz and connected to a bakery there making
cakes, I had difficulty getting the right ingredients as Australia
follows the British standards regarding cake making ingredients.
Most of the baking powder sold in Australian groceries and others
stores contaiin the SAPP only. Its even difficult to find the double
acting type which in addition to the SAPP also contains the CAP acid
salt.
I searched the city ethnic markets where you can buy imported goods
hoping I can buy a good quality baking powder that contains aluminum
salts among its components such as Clabber Girl and Calumet .
Soon I discovered the latter in the shelves. ,,and
It solved my problems with robust bakery cake formulation for my
client..